add indent option to cmdline formatter

pkg/analyzer/bin/formatter.dart

 #!/usr/bin/env dart
 
 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:args/args.dart';
@@ skipping 16 matching lines @@
 final List<String> paths = [];
 
 
 const HELP_FLAG = 'help';
 const KIND_FLAG = 'kind';
 const MACHINE_FLAG = 'machine';
 const WRITE_FLAG = 'write';
 const SELECTION_FLAG = 'selection';
 const TRANSFORM_FLAG = 'transform';
 const MAX_LINE_FLAG = 'max_line_length';
+const INDENT_FLAG = 'indent';
 
 
 const FOLLOW_LINKS = false;
 
 
 main(args) {
   var options = argParser.parse(args);
   if (options['help']) {
     _printUsage();
     return;
   }
 
   _readOptions(options);
 
   if (options.rest.isEmpty) {
     _formatStdin(kind);
   } else {
     paths.addAll(options.rest);
     _formatPaths(paths);
   }
 }
 
 _readOptions(options) {
   kind = _parseKind(options[KIND_FLAG]);
   machineFormat = options[MACHINE_FLAG];
   overwriteFileContents = options[WRITE_FLAG];
   selection = _parseSelection(options[SELECTION_FLAG]);
-  formatterSettings =
-      new FormatterOptions(codeTransforms: options[TRANSFORM_FLAG],
-          pageWidth: _parseLineLength(options[MAX_LINE_FLAG]));
+  formatterSettings = new FormatterOptions(
+      codeTransforms: options[TRANSFORM_FLAG],
+      tabsForIndent: _parseTabsForIndent(options[INDENT_FLAG]),
+      spacesPerIndent: _parseSpacesPerIndent(options[INDENT_FLAG]),
+      pageWidth: _parseLineLength(options[MAX_LINE_FLAG]));
 }
 
+/// Translate the indent option into spaces per indent.
+int _parseSpacesPerIndent(String indentOption) {
+  if (indentOption == 'tab') {
+    return 1;
+  }
+  int spacesPerIndent = _toInt(indentOption);
+  if (spacesPerIndent == null) {
+    throw new FormatterException('Indentation is specified as an Integer or '
+        'the value "tab".');
+  }
+  return spacesPerIndent;
+}
+
+/// Translate the indent option into tabs for indent.
+bool _parseTabsForIndent(String indentOption) => indentOption == 'tab';
+
 CodeKind _parseKind(kindOption) {
   switch(kindOption) {
     case 'stmt' :
       return CodeKind.STATEMENT;
     default:
       return CodeKind.COMPILATION_UNIT;
   }
 }
 
 int _parseLineLength(String lengthOption) {
@@ skipping 90 matching lines @@
   // NOTE: these flags are placeholders only!
   var parser = new ArgParser();
   parser.addFlag(WRITE_FLAG, abbr: 'w', negatable: false,
       help: 'Write reformatted sources to files (overwriting contents).  '
             'Do not print reformatted sources to standard output.');
   parser.addFlag(TRANSFORM_FLAG, abbr: 't', negatable: false,
       help: 'Perform code transformations.');
   parser.addOption(MAX_LINE_FLAG, abbr: 'l', defaultsTo: '80',
       help: 'Wrap lines longer than this length. '
             'To never wrap, specify "Infinity" or "Inf" for short.');
+  parser.addOption(INDENT_FLAG, abbr: 'i', defaultsTo: '2',
+      help: 'Specify number of spaces per indentation. '
+            'To indent using tabs, specify "--$INDENT_FLAG tab".'
+            '--- [PROVISIONAL API].', hide: true);
   parser.addOption(KIND_FLAG, abbr: 'k', defaultsTo: 'cu',
       help: 'Specify source snippet kind ("stmt" or "cu") '
             '--- [PROVISIONAL API].', hide: true);
   parser.addOption(SELECTION_FLAG, abbr: 's',
       help: 'Specify selection information as an offset,length pair '
             '(e.g., -s "0,4").', hide: true);
   parser.addFlag(MACHINE_FLAG, abbr: 'm', negatable: false,
       help: 'Produce output in a format suitable for parsing.');
   parser.addFlag(HELP_FLAG, abbr: 'h', negatable: false,
       help: 'Print this usage information.');
@@ skipping 39 matching lines @@
                      'offset': formatResult.selection.offset,
                      'length': formatResult.selection.length
                   }
     });
 
 /// Log the given [msg].
 _log(String msg) {
   //TODO(pquitslund): add proper log support
   print(msg);
 }